Sue, who works at Memorial University, Newfoundland, Canada, first looked at studies with mice, which he suggests are "good models for human physiology."

Several studies he cited suggest that female mice have stronger immune systems than their male counterparts, and that gender hormones have a direct effect on the immune system.

But it wasn't just in animal studies that the phenomenon could be observed.

A 2013 study from Stanford University found that women's antibodies tend to respond more rapidly to an injection of the flu virus than men's antibodies.

The study also found that men with higher testosterone levels tended to have the weakest antibody response. As a result, the study suggests that testosterone suppresses the immune system, while estrogen boosts it.

The capability of the immune system to deal with infection has more consequences than the occasional sniffle.

Pregnant women reportedly display significantly more extreme flu-like symptoms than non-pregnant women, according to Sue, which proves the connection between hormones and the immune system. Shutterstock/Agnieszka Marcinska

Sue warns that, if these hormones do have a profound effect on the immune system, then "men may not be exaggerating symptoms, but have weaker immune responses to viral respiratory viruses, leading to greater morbidity and mortality than seen in women."

As a result, Sue believes that the common perception of "man flu" as an exaggeration is unjust.

When feeling under the weather, Dr Sue promotes energy conservation. "Lying on the couch, not getting out of bed, or receiving assistance with activities of daily living could also be evolutionarily [sic] behaviours that protect against predators," he advised.

Playing up to the stereotypes of men's reactions to illness, Sue jokingly said: "Perhaps now is the time for male friendly spaces, equipped with enormous televisions and reclining chairs, to be set up where men can recover from the debilitating effects of man flu in safety and comfort."